Hey bro, not sure what the difference is between "dabbling" and a serious cycle is, but 400mg Test with tren is a serious cycle! As for an off season plan, 400mg test along with some EQ would be a good mass building plan. Something like this would work well.
wk 1-12
Test E 400-500mg EW
EQ 400mg EW
adex .5mg EOD to 2x wk as needed
As for GH, the gains aren't nearly as dramatic as with AAS. At this point in the game, you would be best off waiting. It can be helpful when dieting but for your off season, I would wait